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Characterization and Control of Evaporative Emissions from Fuel Tanks in Nonroad Equipment

United States Environmental Protection Agency-Michael J. Samulski
Published 2006-11-13 by SAE International in United States
This paper presents test data on evaporative emissions from fuel tanks used in nonroad equipment. Measurements were made on diurnal, running loss, diffusion, and fuel tank permeation emissions. In this effort, baseline test data were collected on fuel systems that are representative of current nonroad equipment. The impacts of several test parameters on evaporative emissions were also investigated. These test parameters included temperature, fuel type, and test configuration. As temperature increased, evaporative emissions increased in all cases. In addition, blending 10 percent ethanol into the test fuel increased permeation emissions for most materials.Data are also presented on several emission control technologies. For venting emissions, the evaluation included limited flow vent paths, passively purged carbon canisters, and insulation effects. For permeation, the evaluation included surface treatments, barrier layers, and alternative materials. This test data suggests that significant reductions in evaporative emissions can be achieved using these technologies.
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CMS - An Evolution of the CVS - A Full Flow, Constant Mass Flow, Sampling System

United States Environmental Protection Agency-Carl J. Ryan, Joseph McDonald
AVL North America, Inc.-William Silvis, James Williamson, Gerald Marek, Norbert Kreft
Published 2006-04-03 by SAE International in United States
The CMS system commissioned by EPA and built by AVL, is a “start from a clean sheet of paper” approach to a full flow sampling system for aerosol matter from engine exhaust. The challenge of measuring 2007 level post DPF type particulate matter and polyaromatic hydrocarbons led to this re-thinking of sampler design.Previously used CVS designs had evolved to include elements that were not ideally suited for scaling up to large flow rates, and had mixing tunnels that were less than ideal for the sampling of complicated aerosols. The solution presented in this paper used ultrasonic time-of-flight flowmeters in place of the usual Venturi flow tubes, reducing the size and cost of air handling components. Acoustically designed dampeners were used to reduce pulsation disturbances to the flow measurement. In addition, the aerosol mixing tunnel was designed with the aid of CFD simulations to provide a portion of the dilution through the walls of its mixing zone to reduce sample loss from thermophoretic and diffusion deposition.This paper will explain the engineering design considerations and calculations, as…
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Fuel Consumption Modeling of Hybrid Vehicles in PERE

United States Environmental Protection Agency-Edward K. Nam
Published 2005-04-11 by SAE International in United States
The new EPA emissions inventory model, MOVES (MOtor Vehicle Emissions Simulator) models fuel consumption of the on-road fleet in its first draft (2004 version). Future versions will model criteria pollutants. MOVES is designed to combine fleet, activity, and second by second emission rate inputs to produce regional, or national fuel consumption rates. It is primarily a data driven model but for some of the future projections, data is not available. It is necessary to design a model, which can fill these “holes” and future emissions rates in MOVES. The Physical Emissions Rate Estimator (PERE) takes vehicle and drive cycle inputs and simply distributes the energy required to follow the trace to the various components (internal combustion engine, electrical motor, fuel cell, etc). The model is validated to the certification fuel economy of the Honda Insight, Honda Civic, Honda FCX, Toyota Prius (2001, and 2004). It is also compared to a small subset of second by second data. While the model is capable of providing second by second output, it is not explicitly designed to be…
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Dynamometer and On-board Emissions Testing of the Honda Insight and Toyota Prius

United States Environmental Protection Agency-Edward K. Nam, Arvon Mitcham
SENSORS Inc.-Carl Ensfield
Published 2005-04-11 by SAE International in United States
As part of the EPA's ongoing in-use vehicle emissions compliance program, two hybrid vehicles were tested. A 2001 Honda Insight and a 2001 Toyota Prius were tested on a chassis dynamometer at the National Vehicle Fuel and Emissions Laboratory. Both vehicles were run on the Federal Test Procedure drive cycle. Emissions were measured simultaneously using the SEMTECH-G Portable Emissions Measurement System (PEMS) for comparison to the chassis dynamometer bench analyzer. The correlation for cumulative emissions (bag) between dynamometer and on-board analyzer were adequate for CO2, CO, and NOx, though the PEMS HC measurements were low by comparison. The measurements were limited by the very low exhaust volume flow rates on both vehicles. A more sensitive flow meter will be required to measure emissions from vehicles certified to SULEV standards. A more detailed analysis of the second-by-second data indicates that during the driving modes where most of the emissions are occurring (cold start, catalyst breakthrough), both analyzers adequately captured emissions. With improvements to the flow meters, the modal measurements from the PEMS should be more useful…
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Particle Size Distribution from a Heavy-Duty Diesel Engine: Steady-State and Transient Emission Measurement Using Two Dilution Systems and Two Fuels

United States Environmental Protection Agency-Matt Spears, William Charmley
Southwest Research Institute-Imad A. Khalek
Published 2003-03-03 by SAE International in United States
Particle size distribution and number concentration were measured in the dilute exhaust of a heavy-duty diesel engine for steady-state and transient engine operation using two different dilution systems that included a full flow CVS that was coupled to an ejector pump (CVS-EP), and a double-ejector micro-dilution tunnel (DEMDT) that was connected to engine exhaust close to turbocharger outlet. Measurements were performed using a scanning mobility particle sizer (SMPS), an electrical low pressure impactor (ELPI), and a parallel flow diffusion battery (PFDB). Fuels with sulfur content of about 385 ppm and 1 ppm were used for this work.The PFDB performed well in measuring nanoparticles in the size range below 56 nm when compared with the SMPS. This was especially valid when a distinct log-normal size distribution in the size range below 56 nm in diameter, the upper size limit of the PFDB, was present.The dilution method and the sulfur content in the fuel influenced the characteristics of the size distributions significantly under both steady-state and the FTP hot-start transient cycle. The CVS-EP resulted in more particle…
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Development of the Direct Nonmethane Hydrocarbon Measurement Technique for Vehicle Testing

United States Environmental Protection Agency-Carl J. Ryan
California Air Resources Board-Leo Zafonte
Published 2003-03-03 by SAE International in United States
The Automotive Industry/Government Emissions Research CRADA (AIGER) has been working to develop a new methodology for the direct determination of nonmethane hydrocarbons (DNMHC) in vehicle testing. This new measurement technique avoids the need for subtraction of a separately determined methane value from the total hydrocarbon measurement as is presently required by the Code of Federal Regulations. This paper will cover the historical aspects of the development program, which was initiated in 1993 and concluded in 2002.A fast, gas chromatographic (GC) column technology was selected and developed for the measurement of the nonmethane hydrocarbons directly, without any interference or correction being caused by the co-presence of sample methane. This new methodology chromatographically separates the methane from the nonmethane hydrocarbons, and then measures both the methane and the backflushed, total nonmethane hydrocarbons using standard flame ionization detection (FID).The AIGER group has evaluated a commercial instrument (Model 55C) manufactured by Thermo Environmental Instruments, Inc., in vehicle exhaust and evaporative emissions testing. The total measurement time with this instrument is 70 seconds for both methane and nonmethane hydrocarbons. The…
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Heavy-Duty Diesel Truck In-Use Emission Test Program for Model Years 1950 through 1975

United States Environmental Protection Agency-Chad R. Bailey, Carl A. Scarbro, Joesph H. Somers
Southwest Research Institute-Steven G. Fritz
Published 2001-03-05 by SAE International in United States
Criteria pollutants were measured from ten Class 7 and 8 (i.e., gross vehicle weights > 33,000 lb) heavy-duty diesel trucks with engine model years between 1953 and 1975. The data was used by EPA to estimate that period's particulate matter emission rates for these type engines and will be used to develop dose response relationships with existing epidemiological data. Particulate samples were analyzed for sulfate and volatile organic fraction. Carbon soot was estimated. The trucks had particulate emissions of 2 to 10 g/mi as compared to 1 to 6 g/mi for trucks with model year engines from 1975 through the mid-1980s, and less than 1 g/mi for post-1988 trucks.
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In-Use Volatility Impact of Commingling Ethanol and Non-Ethanol Fuels

United States Environmental Protection Agency-Peter J. Caffrey, Paul A. Machiele
Published 1994-03-01 by SAE International in United States
An analysis of the potential Reid Vapor Pressure (RVP) impacts of the commingling of ethanol fuels with non-ethanol fuels has been done. This analysis includes a computer model that tracks such variables as owner brand loyalty, fill-up patterns, ethanol fuel market share and percent ethanol in the fuel tank to determine the RVP boost that is associated with the use of ethanol as a gasoline oxygenate as it intermingles with non-ethanol fuels in vehicle fuel tanks. Results indicate that the use of ethanol oxygenated fuels can cause, in some cases, a significant increase in gasoline RVP, thus leading to higher evaporative emissions.
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Light-Duty Automotive Fuel Economy and Technology Trends Through 1987

United States Environmental Protection Agency-R. M. Heavenrich, J. D. Murrell, J. P. Cheng
Published 1987-09-01 by SAE International in United States
This, the fifteenth in this series of papers, examines trends in light-duty vehicle fuel economy and technology usage for model years 1978 through 1987. Comparisons with previous years’ data are made for the fleet as a whole and for number of cylinders, vehicle size class, inertia weight class, and market segment (Domestic, European, and Asian).
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Fuel Economy and Emissions of a Toyota T-LCS-M Methanol Prototype Vehicle

United States Environmental Protection Agency-J. D. Wiurrell, G. K. Piotrowski
Published 1987-06-01 by SAE International in United States
The Toyota lean combustion system-methanol (T-LCS-M) is a lean burn methanol combustion system designed to maximize fuel economy and driving performance while minimizing pollutant emissions. Testing at the EPA Motor Vehicle Emissions Laboratory (MVEL) indicates that this system allows relatively low emissions of regulated pollutants and aldehydes when operated on either M100 or M85 methanol fuels under transient driving and evaporative emissions test conditions. Total vehicle hydrocarbon emissions appear lower when the vehicle is operated on M100 rather than M85 fuel. Fuel economy is slightly improved when the system is operated on M85 rather than M100 fuel.
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